/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.transforms.windowing;



import com.google.auto.value.AutoValue;

import com.bff.gaia.unified.sdk.coders.Coder;

import org.joda.time.Instant;



import java.util.Collection;

import java.util.Collections;



/**

 * A {@link WindowFn} that assigns all data to the same window.

 *

 * <p>This is the {@link WindowFn} used for data coming from a source, before a {@link Window}

 * transform has been applied.

 */

public class GlobalWindows extends NonMergingWindowFn<Object, GlobalWindow> {



  private static final Collection<GlobalWindow> GLOBAL_WINDOWS =

      Collections.singletonList(GlobalWindow.INSTANCE);



  @Override

  public Collection<GlobalWindow> assignWindows(AssignContext c) {

    return GLOBAL_WINDOWS;

  }



  @Override

  public boolean isCompatible(WindowFn<?, ?> o) {

    return o instanceof GlobalWindows;

  }



  @Override

  public void verifyCompatibility(WindowFn<?, ?> other) throws IncompatibleWindowException {

    if (!this.isCompatible(other)) {

      throw new IncompatibleWindowException(

          other,

          String.format(

              "%s is only compatible with %s.",

              GlobalWindows.class.getSimpleName(), GlobalWindows.class.getSimpleName()));

    }

  }



  @Override

  public Coder<GlobalWindow> windowCoder() {

    return GlobalWindow.Coder.INSTANCE;

  }



  @Override

  public WindowMappingFn<GlobalWindow> getDefaultWindowMappingFn() {

    return new AutoValue_GlobalWindows_GlobalWindowMappingFn();

  }



  @AutoValue

  abstract static class GlobalWindowMappingFn extends WindowMappingFn<GlobalWindow> {

    @Override

    public GlobalWindow getSideInputWindow(BoundedWindow mainWindow) {

      return GlobalWindow.INSTANCE;

    }

  }



  @Override

  public Instant getOutputTime(Instant inputTimestamp, GlobalWindow window) {

    return inputTimestamp;

  }



  @Override

  public boolean assignsToOneWindow() {

    return true;

  }



  @Override

  public boolean equals(Object other) {

    return other instanceof GlobalWindows;

  }



  @Override

  public int hashCode() {

    return GlobalWindows.class.hashCode(); // all GlobalWindow instances have the same hash code.

  }



  @Override

  public String toString() {

    return getClass().getCanonicalName();

  }

}